Paranormal Progress

Several doors in Mob of the Dead cannot be opened with points, only by charging up a voltage meter with in the afterlife. These voltage meters are usually well hidden. One door is to the showers, one door is to the roof, and one door is to the Warden's Office.

Simply look for a door with the afterlife symbol above it. Get downed by zombies or interact with a power box to go into the afterlife. When in the afterlife, you will be able to walk through the door and follow the blue arrows to a voltage meter. Charge the voltage meter with electricity from your hands, and the door opens!